1. Field of the Invention
This invention relates to an apparatus for producing foamed blast furnace slag comprising a revolving conveyor including a bottom and side walls rising from the bottom, which conveyor serves to receive molten slag from a slag feeder, and stationary water-dispensing means adjacent to the slag feeder.
2. Description of the Prior Art
In the production of foamed blast furnace slag, water is injected into the molten slag so that the slag is foamed and cooled. For that purpose it is usual to pour the slag into a tub, which has a bottom that is provided with nozzles, through which the water required to foam and cool the molten slag is discharged under pressure. When the foamed slag has solidified, it is removed from the tub. An important disadvantage of that production of foamed blast furnace slag resides in the fact that the foaming of the slag will result in a formation of sulfur dioxide and hydrogen sulfide at high rates for limited times as by-products, which cannot be removed in a controlled manner. Besides, it is hardly possible to control the foaming operation because a certain amount of water must be supplied first and the slag will foam spontaneously after the water has been supplied.
In an endeavor to permit a continuous processing of the slag it is known from U.S. Pat. No. 2,286,078 to apply the liquid slag to a belt conveyor, which constitutes a trough that comprises a bottom and side walls. Before the slag is applied to the belt, the latter is supplied with water so that the molten slag is caused to foam as the slag poured onto a film or bath of water. Because the foaming is not controlled, that known apparatus is mainly intended to produce granule but is less suitable to produce foamed blast furnace slag, which differs from granules in that it is required to have even at its surface a pore distribution which is as uniform as possible.